html, body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  box-sizing: border-box;
}
.bkRed {
  background-color: red;
}
.colorOrange {
  height: 200px;
  color: orange;
}
/* 五子棋 */
.text {
  margin: 0 auto;
  width: 200px;
  text-align: center;
}
.board-row {
  display: flex;
  margin: auto;
  /* justify-content: center; */
  background-color: rosybrown;
}
.board-row button {
  position: relative;
  width: 40px;
  height: 40px;
}
.board-row .square1::before,
.board-row .square2::before {
  content: '';
  position: absolute;
  top: 2px;
  right: 2px;
  bottom: 2px;
  left: 2px;
  border-radius: 50%;
  animation: circle-size .3s ease-out forwards;
  z-index: 1;
  background-color: white;
}
.board-row .square2::before {
  background-color: black;
}
@keyframes circle-size {
  0% {
    top: -20px;
    right: -20px;
    bottom: -20px;
    left: -20px;
  }
  100% {
    top: 2px;
    right: 2px;
    bottom: 2px;
    left: 2px;
    box-shadow: rgba(0, 0, 0, .3) 2px 2px 5px;
  }
}
@keyframes size {
  0% {
    width: 0;
    height: 0;
  }
  100% {
    width: 200%;
    height: 200%;
  }
}
/* 正方体 */
.box {
  position: relative;
  perspective: 700px;
}
.box .cubebox {
  margin: 100px auto;
  width: 200px;
  transform: rotateX(-20deg) rotateY(30deg);
  transform-style: preserve-3d;
  transform-origin: center;
}
.cube {
  position: absolute;
  width: 200px;
  height: 200px;
  opacity: .5;
}
.cube:nth-child(1) {
  transform: translateZ(100px);
  background-color: cornflowerblue;
}
.cube:nth-child(2) {
  transform: rotateY(90deg) translateZ(100px);
  background-color: antiquewhite;
}
.cube:nth-child(3) {
  transform: rotateY(180deg) translateZ(100px);
  background-color: darkcyan;
}
.cube:nth-child(4) {
  transform: rotateY(-90deg) translateZ(100px);
  background-color: darkturquoise;
}
.cube:nth-child(5) {
  transform: rotateX(90deg) translateZ(100px);
  background-color: darkviolet;
}
.cube:nth-child(6) {
  transform: rotateX(-90deg) translateZ(100px);
  background-color: darkslateblue;
}
